As a conventional switchgear equipped with a high voltage electrical apparatus such as a gas insulated switchgear placed in a vessel filled with insulating gas such as SF6 gas together with electrical apparatuses and high voltage conductors, there is one shown in FIG. 49.
In FIG. 49, a bus bar 4, a gas circuit breaker 5, main circuit conductors 6,7 with high voltage are placed in vessels 1,2,3 and insulating gas such as SF6 gas is filled inside the vessels. Incidentally, a reference numeral 8 denotes an operating panel and 12 denotes an attaching portion of the bus bar to be connected to an adjacent unit.
Furthermore, the vessels 1,2 are formed with opening portions which are for performing assembling work, internal inspection work, or the like, and the vessels 1,2 are provided with covering plates 11,13 which cover the opening portions. Then, during the assembling work or during the inspection work, these covering plates 11,13 are removed and the assembling work or the inspection work for the inside of the vessels 1,2,3 is performed by a worker through the openings.
By the way, heat dissipating fins 21,22 are provided on both surfaces of the outside surface side and the inner surface side of the covering plate 11, respectively. The respective heat dissipating fins 21,22 are arranged so that longitudinal directions thereof are perpendicular when the covering plate 11 is attached to the vessel 2. The heat dissipating fins 22 on the inner surface side of the covering plate 11 are arranged in face-to-face relation to charged portions such as the main circuit conductor 6 arranged in the vessel 2.
In the thus configured switchgear, when a current flows through current conducting portions such as the bus bar 4, the gas circuit breaker 5, the main circuit conductors 6,7 placed in the vessels 1,2,3, Joule heat is generated to increase the temperature of the current conducting portions. Furthermore, an induced current is generated in the vessels 1,2,3 by the current flowing through the current conducting portions; and Joule heat is also generated in the vessels 1,2,3 to increase the temperature thereof.
As described above, the heat generated in the current conducting portions, for example, high heat generated by the main circuit conductor 6 serving as a high temperature portion of the vessel 2, is mainly transferred to the vessel 2 including the covering plate 11 through the insulating gas. Furthermore, the heat transferred to the vessel 2 and the heat generated in the vessel 2 itself are dissipated outside the vessel 2 and, at the same time, such heat is also transferred to the covering plate 11 via the vessel 2. In this case, the heat dissipating fins 22 provided on the inner surface side of the covering plate 1 transfers the heat of the insulating gas to the covering plate 11. In addition, the covering plate 11 itself and the heat dissipating fins 21 on the outside surface side of the covering plate 11 dissipate the heat transferred to the covering plate 11 outside the vessel 2.
Patent Document 1: Japanese Unexamined Patent Publication No. H8-223719